In this paper, a low-cost load cell (force sensor) is presented in which the force to be measured is transformed into a fluid pressure. The design consists of a boss, attached to a membrane, and a bucket-like structure which encloses a fluid volume. This geometry causes a force to be transformed into a pressure. We show that this transformation only depends on the geometrical parameters of the load cell and that it is independent of the Young's modulus of the membrane resulting in very low creep and hysteresis. Experimental results with loads up to 1000 kg show very good repeatability and are in close agreement with both analytical and numerical calculations.